The SU-76 is definitely overperforming with vet vs vehicles and in the AI department with the free low CD barrage.
I'll say once you add numbers it gets annoying, cause 1 Su76 barraging won't do anything. I'll agree that with vet it scales to late game really well.
The SU-76 scales way too well. It's supposed to be a light tank destroyer, but performs as well as the medium tank destroyers. It should be able to take on P4s, but should start suffering vs Panthers and Tigers.
The result I have been seeing is soviet players spamming them well into the late game which is ridiculous. Imagine if axis players were able spam Pumas and destroy IS-2s, that's pretty much what it's like. If soviet players want something to counter panthers and tigers they should be relying on SU-85s not su-76s.
I wouldn't mind seeing the pen lowered across the board by 20.
I wouldn't compare the Puma to the Su76. Compare it with a Stug which is 10mp/15f more expensive. A bit more maneurable platform, +40 dmg, +160hp, Mgs, -10 range (i think with vet it should gain 5-10), less ±0.8 RoF.